Composite yarn

ABSTRACT

A composite matrix yarn (Y) including a cover yarn ( 80 ) formed of a plurality of twisted fibers, a core strand ( 70 ) positioned within the cover yarn ( 80 ) and around which the fibers of the cover yarn ( 80 ) are twisted to provide mechanical adhesion between the cover yarn ( 80 ) and the core strand ( 70 ), and an adhesive binder ( 75 ) carried on the core strand ( 70 ) for providing enhanced adhesion between the core strand ( 70 ) and the cover yarn ( 80 ).

[0001] This application is based upon and claims the filing date of provisional patent application No. 60/190,674, filed on Mar. 20, 2000.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

[0002] This invention relates to a composite construction made from drafted staple fiber, a suitable chemical and/or transformable fiber, and a filament component or components inserted into the approximate strand center by means of air jet and/or open-end spinning techniques. The filament yarn or yarns form a core upon which a binder formed of chemical compound and/or thermoplastic fiber is applied. A staple cover is spun around the core and binder to form the composite yarn. The present invention relates to producing a commercially viable matrix yarn with unique properties and a process to combine several components of mono- or multifilament core, treatment, and cover construction.

[0003] A chemical and/or thermoplastic binder may be applied to the core by means of an emulsion trough or pass-through chamber with metering pump, followed by a heat source if liquid to reduce and/or eliminate the moisture in the resulting yarn. If the binder is a thermoplastic material, a heat source may be deleted. This treated yarn is then fed into the spinning zone to be covered by staple fibers.

[0004] If the binder is to be another fiber, it may be fed as a component of the sliver input. If the binder is to be a (thermoplastic) filament, or in tape/slit film form, it may be fed into the spinning zone parallel to the core material.

[0005] The present invention also provides a method of commercially combining core, adhesive enhancement, and cover by directing a sliver of staple fibers through a drafting zone to achieve the desired coverage; continuously applying an adhesive factor; to cover a continuous core by means of an air jet spinning process (or via DREF equipment).

[0006] The process of spinning yarn from fibers dates back to Egyptian times. Yarns have been composed of natural fibers for centuries. They have typically been all staple fiber, cotton, wool, etc.

[0007] Many synthetic fibers are produced in both continuous filament and staple fiber form. Each fiber form has been developed to exhibit specific, but distinctly different, properties for texture, strength, elongation, shrinkage, bulk and the like.

[0008] Composite spinning or core spinning was developed to enhance the tensile strength of a spun yarn by inserting a filament core surrounded by staple fibers twisted concentrically around it. This has been and is actively done today on ring spinning equipment.

[0009] Core spun yarns may also be made on DREF spinning equipment, which utilizes two oppositely rotating perforated drums to cause entering fibers to be twisted on themselves or onto a filament core. The drums have a vacuum pressure to hold the fibers and to cause their rotating friction to insert the twist. This method may also be referred to as an open end method as the fibers are airborne prior to its spinning action.

[0010] It is known that core spun yarns may be produced by wrapping or spinning a fiber sheath around a continuous filament core. The opposite construction of a continuous filament wrapped around a fiber or staple core may also be employed. These yarns may have their core and/or covering as staple fibers or as filaments interchangeably. Ring spun core/wrapped yarns have been produced for many years, especially for sewing threads. Such yarns may be made on a roving frame or ring frame whereby one or more core strands is presented behind the last, or front, draft roll element and staple fibers are twisted about it.

[0011] Such yarns may also be made on a DREF (TM Dr. Ernst Fehrer, Linz, Austria), friction spinning, Bobtex, electrostatic spinning, “can back” ring spinning, and as in the present embodiments, by using an air jet spinning technique such as practiced on a Muratec MJS jet spinner.

[0012] The following terms are set out by way of definition. Use of the following terms in this application is consistent with the definitions provided unless specifically stated to the contrary.

[0013] Carding: the use of a carding machine to parallel, straighten, clean, and to remove short fibers or trash. The output is called “sliver.”

[0014] Drawing: a process in which one or more ends of sliver are parallel and attenuated/drafted to achieve a high degree of uniformity in a resultant strand. This drawing process may be carried out in multiple passes to enhance the degree of parallelization in the fiber strand.

[0015] Sliver: a rope-like strand of continuous, no twist fibers produced by carding and/or drawing. This sliver is the input for the staple component in DREF, air jet, friction spinning, Bobtex, electrostatic, and “can back”, and roving type (speeder spun) spinning.

[0016] Roving: sliver converted by drafting and adding a small amount of twist to gently bind the fibers together. This process occurs just prior to ring spinning. Roving is normally the fiber input to ring spinning.

[0017] DREF Spinning: Patented system by Dr. Ernst Fehrer of Linz, Austria which drafts one or more slivers via a carding cylinder, introduces them to a pair of rotating perforated insert drums which insert twist in an open end/friction spinning process. This equipment will also operate with a core to result in core spun yarn. This equipment may also be used to accomplish the matrix yarn of subject invention with the choice dependant on size, texture, and other properties of desired yarn. DREF II or DREF III may be used for this process.

[0018] Bobtex and electrostatic spinning: These processes are essentially similar using an electrical field to insert twist into fibers.

[0019] “Can Back” Spinning: Feeding a conventional ring spinning frame with sliver as compared to the normal roving input.

[0020] Roving Spun/“Speeder Spinning”: Using a roving frame to produce yarn direct as compared to roving. Usually this is a very slow production method.

SUMMARY OF THE INVENTION

[0021] Therefore, it is an object of the invention to provide a composite matrix yarn which includes properties of both filament and spun yarn.

[0022] It is another object of the invention to provide a composite matrix yarn has both excellent mechanical and chemical adhesion.

[0023] It is another object of the invention to provide a composite matrix yarn which can be manufactured from a wide variety of cover fibers, core fibers and adhesives.

[0024] These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a composite matrix yarn, comprising a cover yarn formed of a plurality of twisted fibers, a core strand positioned within the cover yarn and around which the fibers of the cover yarn are twisted to provide mechanical adhesion between the cover yarn and the core strand, an adhesive binder carried on the core strand for providing enhanced adhesion between the core strand and the cover yarn.

[0025] According to one preferred embodiment of the invention, the core strand is chosen from the group consisting of wire, spun yarn, monofilament yarn and multifilament yarn.

[0026] According to another preferred embodiment of the invention, the cover yarn comprises staple fibers chosen from the group consisting of natural fibers and synthetic fibers.

[0027] According to yet another preferred embodiment of the invention, the adhesive binder is chosen from the group consisting of isocyanate, natural rubber latex, butadiene rubber latex, vinylpyridene, styrene butadiene rubber, terpolymer rubber latex, sbr copolymer rubber latex, chloroprene rubber latex, acrylonitrile butadiene copolymer rubber latex, rfl resorcinol formaldehyde latex, hot melt adhesive, pvc polyvinyl chloride, urethane, natural glue, synthetic glue, natural wax and synthetic waxes.

[0028] An embodiment of the method according to the invention comprises the steps of forming a sliver of staple fibers, drafting the sliver into a yarn, introducing into the drafted sliver a core strand to form a composite yarn, said core strand having thereon an adhesive binder for providing enhanced adhesion between the core strand and the cover yarn, and twisting the composite yarn to impart mechanical adhesion thereto.

[0029] According to yet another preferred embodiment of the invention, the step of drafting the sliver comprises the step of drafting the sliver on an open-end spinning machine to form the sliver into a yarn.

[0030] According to yet another preferred embodiment of the invention, the method includes the step of plying the composite yarn.

[0031] According to yet another preferred embodiment of the invention, the method includes the step of introducing the core strand into the drafted sliver comprises introducing a strand chosen from the group consisting of wire, fiberglass, aramid, polyethylene, polyester, rayon, polypropylene, polyolefin and nylon.

[0032] According to yet another preferred embodiment of the invention, the adhesive binder is chosen from the group consisting of isocyanate, natural rubber latex, butadiene rubber latex, vinylpyridene, styrene butadiene rubber, terpolymer rubber latex, sbr copolymer rubber latex, chloroprene rubber latex, acrylonitrile butadiene copolymer rubber latex, rfl resorcinol formaldehyde latex, hot melt adhesive, pvc polyvinyl chloride, urethane, natural glue, synthetic glue, natural wax and synthetic wax.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Some of the objects of the invention have been set forth above. Other objects and advantages of the invention will appear as the invention proceeds when taken in conjunction with the following drawings, in which:

[0034]FIG. 1 is a schematic representation of a yarn spinning apparatus constructed according to the present invention;

[0035]FIG. 2 is a schematic representation of the portion of the yarn spinning apparatus which applies the filament core to the drafted cover yarns;

[0036]FIG. 3 is an enlarged side view of a matrix yarn according to an embodiment of the invention; and

[0037]FIG. 4 is an enlarged, schematic cross-sectional view of the completed matrix yarn.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE

[0038] Referring now specifically to the drawings, a schematic diagram of a Murata MJS Jet Spinner (“MJS”) machine which can be configured to produce a yarn according to the present invention is illustrated in FIG. 1 and shown generally at reference numeral 10. Machine 10 includes a drafting zone 20, a spinning zone 30 and a winding zone 40. In conventional jet spinning, a drawn sliver “S” is supplied directly to sets of upper and lower drafting rolls 21, 22, where the sliver is drafted by moving the generally longitudinally-extending fibers past each other in a controlled manner and at controlled rate. The drafted fibers pass through two compressed air nozzles 31, 32 in the spinning zone 30. Compressed air discharged by nozzle 31 whirls about the axis of the nozzle in a direction opposite that discharged by the nozzle 32, thus producing a yarn. The nozzle 32 gathers a group of fibers fed from the drafting rolls 21, 22 by false twisting. Between the front roller in the drafting zone 20 and nozzle 32 the compressed air discharged by nozzle 31 rotates about the axis of nozzle 31 in the direction opposite to that in which the nozzle 32 gathered and twisted the fibers, creating a counter-whirling force opposite to that with which the core fibers were twisted by the nozzle 32. Thus, some fibers are separated during this false twisting.

[0039] The counter-whirling force generated by the nozzle 31 coils the separated fibers around the previously-twisted fibers in the direction opposite to that with which the previously-twisted fibers were twisted by the nozzle 32. The fibers that passed through the nozzle 32 are more tightly wrapped around the previously-twisted fibers by the untwisting force resulting from the false twisting.

[0040] The twisted yarn then passes into the winding zone where the yarn is wound onto a take-up package “P” in the form of a matrix yarn “Y”.

[0041] In the practice of the present invention, the filament yarn “F” is fed into the sliver downstream of the last drafting zone and is integrated into the sliver bundle before twisting begins in the spinning zone 30. As is shown in FIG. 2, the filament yarn “F” is fed from a supply package 14 through a pigtail guide 15, a tension device 16, a feeler 17 and an air sucker 18. The filament “F” is then passed through a core yarn delivery tube 19 and then into a sliver delivery tube 26, where the integration of the filament yarn “F” and the sliver “S” occurs. The filament yarn “F” should be introduced into the center of the sliver “S”. Since drafting has already taken place, the filament yarn “F” becomes the core of the matrix yarn “Y”.

[0042] The system produces a new product which encompasses the properties of both filament and spun yarn, with the filaments having thereon a coating of suitable chemical adhesion product. Yarns can be made in right hand “Z” or left hand “S” twist direction. Alternatively, other spinning methods may be considered as described above, especially the DREF equipment, but the desired yarn properties and economics of production speed are to be considered.

[0043] The chemical treatment may be in the form of transformable or thermoplastic filaments as all or part of the core; or it may be composed of transformable or thermoplastic staple fibers as all or part of the cover; or it may be a combination of all three methods.

[0044] The chemical treatment may also be in the form of a wax disc or block which marks off onto the core yarn.

[0045] The percentages of core and cover fiber may be varied over a wide range depending on the yarn properties desired, especially for strength and “strike through” for adhesion to rubber and/or plastic compounds. The present invention presents numerous advantages over current yarns.

[0046] The new yarn represents one product that may be used to perform the work of two current yarns used individually—namely bare or treated filament yarn or basic spun yarn. This allows the user to carry one inventory with more flexibility and lower total cost. The percentages of core, adhesive treatment, and cover may be varied over a wide range to design the resultant yarn to performance requirements. The adhesive material and/or interlacing of fibers in spinning allow the yarn to process well without stripping or shedding fibers. These yarns may be used as single ends or they may be plied. A representational view of the yarn is shown in FIG. 3.

[0047] The core material may be wire, a spun yarn, monofilament, or multifilament in any fiber type. The choice is a matter of yarn design, cost, and performance needs. The choice of adhesion method allows one to build a matrix yarn with filament tenacities further enhanced by both mechanical and chemical adhesion. Current treated filament yarns have chemical adhesion, but poor mechanical adhesion. Likewise, current spun yarns have good mechanical adhesion, but lack chemical grip. Once braided, spiraled, woven, knitted, or otherwise made into its end product, these matrix yarns enhance the properties and/or cost of these products by enhancing cover factor to reduce cost, build wall or fabric thickness, improving tear resistance, increasing abrasion resistance, enhancing tensile strength, burst strength of the final product, improving bending radius, adding flexibility, and improving toughness, impact resistance, impulse cycles.

[0048] The matrix acts as an integral part of the end-use product. By proactive design of this matrix yarn cost is improved by allowing one inventory item to be used as opposed to both filament and spun yarns as separate items. Cost is improved by permitting a wider choice of filament and/or fiber components. Color is added by utilizing colored components; e.g. solution dyed fibers. Use of the process creates fewer knots or splices per pound of yarn to cause defects in fabrics. Enhanced downstream processing by the customer results.

[0049] The benefits of a spun yarn surface are provided together with the tensile factor of filament. Efficient use of exotic, expensive fibers is permitted, while shortened production times result from fewer processes.

[0050] Although the ring and DREF equipment will suffice to construct the yarn described in the present invention, air jet spinning has been chosen because of its speed of manufacture and the presence of automation. These factors greatly influence the cost of yarn production. Air jet was also chosen because it makes very uniform and even textured yarn.

[0051] Air jet spinning is capable of speeds in excess of 350 meters per minute. The principle of air jet spinning applies to effect the matrix yarn of this claim. See U.S. Pat. No. 4,497,167 Nakahara et al. Single or dual nozzles may be used.

[0052] The present invention is a method for manufacturing a yarn of staple fibers and mono or multifilament yarn(s). The multifilament yarn is first treated chemically or thermoplastic fiber and/or filaments are added before entering an air jet spinning zone where staple fibers are spun around the whole strand. The tension on the core material is enough to allow continuous spinning, but loose enough to allow some random fiber migration of the staple cover into a multifilament bundle. No such migration takes place with wire or monofilament cores.

[0053] The completed matrix yarn “M” is immediately wound onto tubes or cones by the onboard winder. Yarn break repairs are made automatically by the machine's knotter/splicer.

[0054] One aspect of the present invention is to provide a three component composite yarn, including a filament core, adhesive binder (chemical, fiber, filament, or tape), and a staple fiber cover in natural or colored fiber.

[0055] It also provides a method of commercially combining core, adhesive enhancement, and cover by directing a sliver of staple fibers through a drafting zone to achieve the desired coverage; continuously applying an adhesive factor, to cover a continuous core by means of an air jet spinning process.

[0056] It provides a flexible method of producing yarn by the above method. Each yarn product may be engineered to achieve the necessary end use performance requirements. To a person skilled in the art of making yarns, these and other aspects of the present invention will become apparent after reading the attached drawings.

[0057] The following examples are illustrative of the range of products which can be made in accordance with the processes of the invention. CORE ADHESIVE COVER 1. 320 den fil poly, 50 Lord Corp. HT Poly staple filament Dupont 68L, Chemlok 855 1.375 Den × 1.5″ 8.3 gpd, 18.8% elongation 7.3% shrinkage @ aqueous 6.5 gpd, 4.0% 177C 30 minutes w/ adhesive shrinkage producer's twist 2240 den core none same as above applied @ 4915 den 7/2.52 31.3% 68.69% Total denier 7155, single end tensile approx. 70 lbs 2. 600 den fil poly Lord Corp. same 3. 1000 den fil poly, Lord Corp. same 192 filament Dupont 68, 9.2 gpd, 16.3% elongation 11.6% shrinkage @ 177C 30 minutes w/ producer's twist 4. 840 den nylon, 140 Lord Corp. same filament Dupont 728, 9.5 gpd, 20.0% elongation 7.0% shrinkage @ 177C, 2 minutes w/producer's twist 5. 320 den poly Lord Corp. Sol Dyed Colored polyester 1.2 or 1.5 Den × 1.5″ 6. 600 den poly pp or pvc fiber HT poly staple 7. 200 den Keviar Lord Corp. HT poly staple (TM Dupont) 134 filament Dupont 964, 23.8 gpd, Chemlok 855 3.0% elongation Less than 1.0% shrinkage @ 177C w/producer's twist This equates to a 8/4 ply commonly used in hose braiding. 800 den core 2% 1819 den cover 4/2.52 30% 68% Total denier 2657, single end tensile approx. 68 lbs.

[0058] These matrix yarns may be used by themselves as a single strand or they may be plied in multiple strands with a sufficient amount of ply twist to maximize strength and complement the end use.

[0059] Adhesive material examples, but not limited to:

[0060] Isocyanate

[0061] Rubber latex

[0062] Butadiene rubber latex

[0063] Vinylpyridene

[0064] Styrene butadiene rubber, terpolymer rubber latex

[0065] SBR copolymer rubber latex

[0066] Chloroprene rubber latex

[0067] Acrylonitrile butadiene copolymer rubber latex

[0068] RFL Resorcinol Formaldehyde Latex

[0069] Hot melt adhesives

[0070] PVC Polyvinyl chloride

[0071] Urethanes

[0072] Various glue products, natural and synthetic

[0073] Waxes

[0074] Adhesives may be applied as a solid, liquid, or foam.

[0075] Typical Applications for these matrix yarns include:

[0076] Broad or Narrow belting

[0077] Narrow fabrics

[0078] Solid or hollow braids

[0079] Rubber or plastic hoses

[0080] Fire hose

[0081] Nonwovens

[0082] Needlepunch fabrics

[0083] Packings, gaskets, seals

[0084] Friction products

[0085] Gloves

[0086] Rope

[0087] Specialty Threads

[0088] Wire or cable reinforcement, insulation

[0089] Reinforcement fabrics, including rubber calendered fabrics

[0090] Medical casting material

[0091] Impact resistant fabrics

[0092] Non-electric panels

[0093] Tires—original manufacture

[0094] Tires—recapped, retreaded

[0095] Other woven, knitted, needlepunched, malimo, maliwat, malipole, triaxial woven, braided, or spiraled fabric constructions

[0096] According to one preferred embodiment of the invention shown in FIG. 4, the core bundle is formed of a multifilament strand 70. A chemical and/or thermoplastic treatment or binder 75 is applied to the strand 70 which is conducive to plastic or rubber chemical adhesion and to the staple cover to be added. A staple cover of drafted staple fibers 80 is applied over the core strand 70 which also promote mechanical adhesion in plastics and/or rubber products and provide impact and abrasion protection to the core strand 70. This cover may be applied in varying percentages based on the weight of the whole resultant yarn and taking into account the desired effect in the end product to be made from this yarn. The multifilament yarn or wire may have twist, be producer's twist, or have no twist at all. If needed, This core material may be wire, fiberglass, aramid, polyethylene, polyester, rayon, polypropylene, polyolefin, nylon, or any other commercial fibers, alone or in combination.

[0097] The staple cover 80 may be 1% to 99% of the total weight and may be composed of vegetable, organic, regenerated, new or virgin, and/or synthetic material or any combination thereof.

[0098] The binder may be thermoplastic or low melt fibers blended into the staple cover or fed parallel in sliver form.

[0099] Fabrics made from the matrix yarn may be knitted, flat woven, triaxially woven, braided, spiralled, or made by other means. These products exhibit high strength, excellent abrasion resistance, and special features to create chemical and/or mechanical adhesion to plastics and rubber goods.

[0100] A matrix composite yarn is described above. Various details of the invention may be changed without departing from its scope. Furthermore, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation—the invention being defined by the claims. 

I claim:
 1. A composite matrix yarn, comprising: (a) a cover yarn formed of a plurality of twisted fibers; (b) a core strand positioned within the cover yarn and around which the fibers of the cover yarn are twisted to provide mechanical adhesion between the cover yarn and the core strand; and (c) an adhesive binder carried on the core strand for providing enhanced adhesion between the core strand and the cover yarn.
 2. A composite matrix yarn according to claim 1, wherein the core strand is chosen from the group consisting of wire, spun yarn, monofilament yarn and multifilament yarn.
 3. A composite matrix yarn according to claim 1, wherein the cover yarn comprises staple fibers chosen from the group consisting of natural fibers and synthetic fibers.
 4. A composite matrix yarn according to claim 1, wherein the adhesive binder is chosen from the group consisting of isocyanate, natural rubber latex, butadiene rubber latex, vinylpyridene, styrene butadiene rubber, terpolymer rubber latex, sbr copolymer rubber latex, chloroprene rubber latex, acrylonitrile butadiene copolymer rubber latex, rfl resorcinol formaldehyde latex, hot melt adhesive, pvc polyvinyl chloride, urethane, natural glue, synthetic glue, natural wax and synthetic waxes.
 5. A method of constructing a composite matrix yarn, comprising the steps of: (a) forming a sliver of staple fibers; (b) drafting the sliver into a yarn; (c) introducing into the drafted sliver a core strand to form a composite yarn, said core strand having thereon an adhesive binder for providing enhanced adhesion between the core strand and the cover yarn; and (d) twisting the composite yarn to impart mechanical adhesion thereto.
 6. A method according to claim 5, wherein the step of drafting the sliver comprises the step of drafting the sliver on an open-end spinning machine to form the sliver into a yarn.
 7. A method according to claim 5, and including the step of plying the composite yarn.
 8. A method according to claim 6, wherein the step of introducing the core strand into the drafted sliver comprises introducing a strand chosen from the group consisting of wire, fiberglass, aramid, polyethylene, polyester, rayon, polypropylene, polyolefin and nylon.
 9. A method according to claim 6, wherein the adhesive binder is chosen from the group consisting of isocyanate, natural rubber latex, butadiene rubber latex, vinylpyridene, styrene butadiene rubber, terpolymer rubber latex, sbr copolymer rubber latex, chloroprene rubber latex, acrylonitrile butadiene copolymer rubber latex, rfl resorcinol formaldehyde latex, hot melt adhesive, pvc polyvinyl chloride, urethane, natural glue, synthetic glue, natural wax and synthetic wax. 